In Minecraft, a fountain of cats at the top of the world

271kochu created a "fountain of cats" in Minecraft by building a structure that extended to the top of the world, then exploiting the game's simple flocking rules for virtual cats to entice the sprites to form a never-ending fountain that is a joy to behold.

You can tame certain animals (wolves and ozelots), and the ozelots turn into domestic cats (don’t ask why). To prevent pets from being left behind and despawning when chunks are unloaded from being out of range (and therefore lost forever), they teleport to you if you’re too far away.